DESCRIPTION (Applicant's abstract): Nonulcer dyspepsia is a highly prevalent medical condition affecting up to 30 percent of the Western population, accounting for 2-5 percent of all visits to primary care physicians and leads to over one billion dollars worth of upper endoscopy procedures per year. In an attempt to lower this tremendous burden on the health care system the general practice currently is to attempt to avoid endoscopy in the majority of patients, which are low risk, by an initial empiric trial of medication. Endoscopy can then be performed on those that fail initial therapy. Unfortunately, empiric treatment is only effective in about 40-50 percent of cases since it is difficult to determine in advance the most effective treatment. Consequently the high cost of endoscopy continues to be a problem. The overall goal of this project is to develop an inexpensive, non-invasive test for the objective and quantitative categorization of nonulcer dyspepsia patients with the purpose of providing the most effective initial treatment. The effectiveness of objective patient categorization will be tested with respect to ability to predict which patients will be responders to acid suppression therapy and which will be responsive to prokinetic treatment.